Cast Iron carbon transfer

[gote]

This really seems to be alchemy but-

The first time I read about it the source was not quite reliable so I did not believe it but I have now seen it in a more reliable source so I start wondering. My question is: Has anyone of you tried it?

The magic procedure is to "smear" cast iron on hot mild steel and create a kind of case hardening. The cast iron of course has excessive carbon and it might transfer if both pieces are hot enough but.....

[ThomasPowers]

well I first ran into it in the UN manuals on Blacksmithing which I consider to be a fairly sound source; but I haven't tried it---yet.

[SLAG]

T. P.

I also was intrigued by the F. A. O.   reference that mentioned carburizing mild steel by heating it, and welding it with cast iron strips or cast iron particles.  The first book in that three volume series  is

FAO AGRICULTURAL SERVICES BULLETIN 88/1

Agricultural engineering in development

Basic blacksmithing: a training manual

by
J. B.Stokes

That reference mentions the method can be found at the end of the booklet. It states; 

CAST IRON

Not used for forge work but can be used as a hard-facing material on low-carbon steels. The job is brought to a bright yellow heat in the forge and flux and cast iron applied to the surface. Cast iron is smeared on to the work. Remove from the fire and allow to cool to a dull red heat, then quench in water. An extremely hard surface will result. Depending on the job, the finish can be left rough or ground to a better finish.

Where there is a shortage of carbon steel, a mixture of cast iron and mild steel can be used for some purposes. Cast iron is smeared on to the surface of a piece of mild steel, more flux added and a second piece of mild steel placed over the cast-iron face. The whole is heated until the cast iron is molten and then the whole is squeezed together in a vice with large jaws. Next, bring to a good welding heat with flux and hammer together. The piece can be cut through and re welded a number of times. The resulting steel can be made into a wide range of woodcutting tools and serves well as ploughshare steel.

I am intrigued by his narrative and will probably try it out in a month or two. Just as an exercise.

The Stokes reference was written for aspiring blacksmiths in rural underdeveloped regions. More specifically, Africa. Some remote areas may not  have access to high carbon steel scrap.(which is hard to imagine),  Hence description and instruction of this carburizing-like process.

Mr. Stokes further elaborates the procedure in his second booklet, http://www.fao.org/3/a-ah635e/index.html  as follows

 

Some applications of cast iron as a hard-facing material

Material. Low-carbon (mild-steel) work piece, cast iron welding rod (not electrodes used for welding cast iron) or pieces of broken cast iron; powdered borax or a commercial cast-iron or bronze-welding flux.

Additional tools. Grinding equipment if this work is performed on tools.

METHOD

Where steel suitable for the making and repairing of ploughshares, ridged points, landsides and similar equipment is not available, the smith often has to use low-carbon steels. They may also have to be used in tool making. For several kinds of tools the wearing life of parts subjected to abrasion can be prolonged by re-facing the most affected parts of jobs.

Where there is a lack of suitable steels, there is almost always a lack of modern hard-facing and wear-resisting materials. Even when available, they are often too expensive for use in rural areas of developing countries. In addition, they usually require electric-arc or oxyacetylene welding equipment, which again is not always available. Nevertheless, given a good blacksmith's fire, flux, cast iron and a little practice, cast iron can be applied to low-carbon steels that, when quenched from high temperature, will give a very hard surface. Although not as effective as the use of modern alloys, this treatment does prolong the life of wearing parts and allows some tools to be made from low-carbon steels.

The application of cast iron is far from a new idea. It has been used by smiths for many generations and was of prime importance when only wrought iron and pig or cast iron were available. The process is made possible because of the difference in the melting temperatures of wrought iron and low-carbon steel and that of cast iron. Wrought iron melts at more than 1 500°C, mild steels at about 1 420°C and cast irons at 1 280° to 1 350°C, depending on how much carbon is present in the iron. Cast iron passes through a "pasty" stage when melting and does not become really fluid until a fluxing agent is applied.

If cast-iron welding rod is used, the application is fairly easy. If broken pieces of cast iron are used, they should be of fairly thin section. Pieces from old cylinder blocks or cylinder heads of motor vehicles are quite good. Pieces need to be of sufficient length to be held in tongs without overheating. Flux should be placed close to the fire, perhaps on a metal dish.

The work piece is heated at the part to be treated to a bright yellow or nearly white heat. While this heating is taking place, the cast iron is also heated. As the cast iron nears the melting point, it will sag toward the fire. Dip the cast iron in to the flux, reheat a little and then apply it to the job by rubbing it on to the heated part of the work. The cast iron can be spread fairly easily on to the work and a buildup will be observed. Sufficient thickness is 1 to 2 mm. More can be deposited if needed. During this operation the work remains in the fire. Allow it to cool to a dull red heat and quench it in water. No additional work is required on jobs such as those shown in Figs 172 to 173.

Figure 172

Figure 173

For hammers and suchlike only the faces are treated in turn and, after quenching, these need to be ground smooth. It is a good idea to practice this operation on a scrap piece of mild steel with cast iron and flux before attempting it on an important job. You will learn by experience the best angles to hold the job in the fire and how to judge temperatures.

Although cast iron is a very brittle material, it is so modified during this operation, as well as being backed up by the tough mild steel, that it can be used with confidence on hammer faces without fear of cracking.

I have been a little long in quoting Mr. Stoke's narrative but I wished to err on the side of inclusiveness.

Regards to all.

SLAG.

 

[ThomasPowers]

Makes my fingers ache just to see all that typing!  Thanks; I have the manuals.  Hmm I still have some of the bathtub cast iron.  I wonder if the porcelain covering would work as a flux...

[SLAG]

The whole carburizing process reminds of Huntsman's invention for making cast steel that was usable for clock springs. I'm sure you are aware of the process and history of it. But some of the I.F.I. might not & could profit from the information., and also, perhaps find it fascinating.

Mr. Huntsman acquired come Swedish blister steel, as a starting material. The Swedish iron ore and wrought iron had little sulfur and phosphorus. The steel was almost pure iron with very little impurities. In order to make blister steel, Swedish iron makers packed iron bars in air-tight boxes and heated it for a long time. The boxes also had carbonaceous material packed in with the iron. (e.g. hoof trimmings, bark, and other vegetable matter). All that heating caused some carbon to go into solution with the iron. A process now known as carburization. The resultant product was called blister steel. Because it had a mottled colorization. The carburization was not uniform. And clock springs had to be of uniform consistency or they would break. Huntsman and co. broke up the blister steel and heated it in small crucibles together with a flux that was used by glass makers. ( I forget what it is but I will look it up soon).The furnace he used resembled glass makers' furnaces that the glass making trade used. These furnaces reached a much higher temperature than standard furnaces of the day. The iron actually melted and the flux carried off impurities. The resultant product was uniform high carbon steel. The cost was very high. But smiths were stuck with it They welded strips of that steel with wrought iron to make axes etc. All this changed with the invention of the Bessemer steel making process, of !855 and 1856. simultaneously invented by the Englishman Sir Henry Bessemer, and the American Mr. Kelley.

Mr. Stokes process of welding and mixing of cast iron with mild steel is in some ways  similar to Mr. Huntsman's process. The attendant story of Mr. Huntsman's trade secret and industrial espionage is also a fascinating tale. But that subject is for another day.

I trust that some of our fraternity will enjoy this post

I really love industrial history and technology., & enjoy being able to share it with others.

Cheers,

SLAG.

Edited August 18, 2016 by SLAG
more added detritus

[ThomasPowers]

Great; do you own a copy of "Steelmaking Before Bessemer, Vol I Blister Steel and Vol II Crucible steel". K.C. Barraclough ?  Also "Sources for the History of the Science of Steel 1532-1786" C.S. Smith and if you are really hardcore "The Knight and the Blast Furnace" Alan Williams foremost recent work on the metallurgy of renaissance armour.

[SLAG]

T. P.

Thank you very much for those references. No I do not have them in my reference library.

 I will suggest them for Margaret's "Dan's Christmas present" wish list. They sound like wonderful snowy, winter evening reading!

Your suggestions are very much appreciated.

Regards.

SLAG.

[TwistedCustoms]

Thanks to SLAG and Thomas for the effort typing out the info and siting sources. Very interesting stuff. Also a reminder that my local library is sub-par. Thank God for inter library loan!

[ThomasPowers]

Think it's subber par than rural NM? ditto on the ILL!

[gote]

Thank you for writing it up. It is tempting to try as hardfacing on tools where the edge is on the side such as wood working chisels and sushi knives. I can imagine  a way where more or less powdersd cast Iron is spred with flux on top of a piece of mild steel that is slowly heated to 1300 °C.